Snap action construction

ABSTRACT

A snap blade construction comprising a generally rectangular flat blade having side strips interconnected at each end. Extending inwardly from the side strips are projections or fulcrums. A self-retaining post member is inserted between the projections to stress the blade so that it will assume either one of two stable states and will move with a snap action between the two states.

United States Patent Inventor Theodore Y. Korsgren 464 Taulman Road,Orange, Conn. 06477 Appl. No. 3,599 Filed Jan. 19, 1970 Patented Jan. 4,1972 SNAP ACTION CONSTRUCTION 21 Claims, 17 Drawing Figs.

U.S. Cl. 200/76, 200/67 D Int. Cl H0lh 15/18 Field of Search 200/67 D,76; 74/100 P References Cited UNITED STATES PATENTS 7/1949 Martin 200/762,608,628 8/1952 Dietrich 200/76 2,624,819 1/1953 Spina et al. 200/67 DUX 2,734,959 2/ 1956 Immel 200/67 D UX 3,061,694 10/1962 Carlson 200/67D UX 3,449,534 6/1969 Bauer 200/67 D UX FOREIGN PATENTS 450,521 4/ 1968Switzerland 200/67 D UX Primary Examiner-David Smith, Jr. Attorney-Deliaand Montgomery ABSTRACT: A snap blade construction comprising agenerally rectangular flat blade having side strips interconnected ateach end. Extending inwardly from the side strips are projections orfulcrums. A self-retaining post member is inserted between theprojections to stress the blade so that it will assume either one of twostable states and will move with a snap action between the two states.

, I 0 39 T 4 "I'm 36 m 35 INVENTOF? Weed on: Y. Kovsqren PATENTED JAN 4m2 SHEET 2 BF l Theo dare Kovsqvan Dex o W9 wwm PATENTEU JAN A I972EHEET W []F Q m GE wwnw 0 K W o w 6 m ATTORNEYS W W W M m w SNAP ACTIONCONSTRUCTION This invention relates to snap blade constructions.

The invention is particularly useful in the art of snap actionelectrical switches and, accordingly, will be disclosed in preferredembodiments in such environments. The prior art is replete with variousdesigns of snap action switches, sometimes referred to as grass hopperswitches which generally comprise a switch blade of substantiallyrectangular outline which is stressed longitudinally of the majordimension thereof and the switch is provided with some central actuatingmember such that when the actuating member is moved transversely to theblade and the ends of the blade are retained, the blade will snap fromone direction of concavity to the opposite.

These devices have found wide use in various types of switchingenvironments requiring a snap action. However, the blades havelimitations that when actuated both ends thereof do not necessarilytravel parallel and a cocking action between the extremities of theblade could occur. This possibility decreases the degree or probabilityof stability of such switches. The presently known switches of thisgeneral type also present some problem in assembly in that the blade andthe actuating member are not mutually self-retaining when not in thehousing.

Accordingly, the present invention is intended to overcome thelimitations of these known switches and provide a stable snap switchhaving a pair of contact ends which may be symmetrically located withrespect to an actuating member, may be asymmetrically located withrespect to an actuating member to provide greater movement of one switchend with respect to the other, and may further be so arranged that thenormal actuating member is held stationary and one end of the blade issnapped through actuation of the other end.

These results are achieved by providing a snap blade of generallyrectangular outline to provide generally parallel arms tenninating ateither end thereof in contact portions. In a normal symmetrical designwhere it would be used as a double-break switch an actuating member ismounted to the blade member in such a manner that the arms of the bladeare stressed both in tension and in torsion. This stresses the switchblade such that in the construction described one end always movessymmetrically with the other and the blade will snap from one degree ofconcavity to another. Moreover, the construction is such that theactuator-to-blade construction is always selflretaining.

Accordingly, an object of this invention is to provide a new andimproved snap blade construction.

Another object of this invention is to provide a new and improved snapblade construction of improved stability.

A further object of this invention is to provide a new and improved snapblade construction utilizing a blade which is stressed both in tensionand in torsion to provide increased stability of operation.

A still further object of the invention is to provide new and improvedsnap acting switches and an improved method of making the same.

The features of the invention which are believed to be novel areparticularly set forth and distinctly claimed in the concluding portionof this specification.

However, the invention both as to its organization and operation,together with further objects and advantages thereto, may best beappreciated by reference to the following detailed description taken inconjunction with the drawings, wherein:

FIG. 1 is a plan view of a blade construction embodying the invention;

FIG. 2 is a plan view of the blade of FIG. 1 with an actuating memberassembled thereto;

FIG. 3 is a view seen in the plane of lines 3-3 of FIG. 2;

FIG. 4 is an end view of the assembly of FIG. 2 showing the blade in onestable condition;

FIG. 5 is an endview of the blade of FIG. 2 showing the blade in anotherstable condition;

FIG. 6 is an isometric exploded view, diagrammatically setting forth aswitch construction embodying the invention;

FIGS. 7 and 8 are diagrammatic views of the switch blade of FIGS. 2 and6 in a double-make, double-break arrangement in various stages ofoperation;

FIG. 9 is a perspective view partially in section of another snap actionswitch embodying the invention;

FIG. 10 is a view in section of still another snap action switchembodying the invention;

FIG. I] is a view seen in the plane: of lines 11-11 of FIG. 10;

FIG. 12 is a half section view through still another switch mechanismembodying the invention;

FIG. 13 is a bottom view of still another switch mechanism embodying theinvention;

FIG. 14 is a view seen in the plane of lines 14-14 of FIG. 13, and

FIG. 15 is a view seen in the plane of lines 15-15 of FIG. 14.

FIG. 16 is a sectional view of a portion of a switch housing embodyingthe invention; and

FIG. 17 is a view seen in the plane of lines 17-17 of FIG. 16.

A snap blade embodying the invention in one form thereof is generallyindicated by the reference numeral 10 and is of generally rectangularshape having spaced apart side strips or margins 11 and 12 which arefurther defined as spaced apart pairs of arms 11a, 11b, 12a, 12b andjoined at either end by end portions 13 and 14, respectively. Projectingfrom the margins towards each other intermediate of the ends areprojections 15 having edges 16 spaced apart. a distance D when the blade10 is in the relaxed position. Edges 16 may be relieved by cutouts 17(shown in broken line) to define a substantially circular aperture. Thispermits the use of a tapered screw (not shown) to spread the arms 15apart.

The blade 10 as shown in FIG. 1 is formed from a flat piece of metallicmaterial and is so shaped that the margins 11 and 12 are slightly bowedwith elbows 18 in the medial portions thereof in the area of theprojections 15. Blades utilized in the invention are one-piecestructures which may be stamped, etched or otherwise formed from a flatflexible metallic sheet.

The blade 10 is assembled to a member which is hereinafter referred toas a post or spreader 19. The post may be utilized as, an actuatingmember when the assembly is used in one application and may also beutilized as an anchoring member in other applications. As shown moreclearly in FIG. 3, the post is formed with indentations or notches 20 onopposite sides thereof which receive a portion of projection 15 and theedges 16 of projections 15 are preferably received on a flat 21 at thebottom of notch 20. The notch 20 is further defined by walls 22 and 23which act to retain the projections 15 and further act to define thelimits of motion. It has been determined that an angular relationship ofapproximately 30 degrees between the walls 22 and 23 is preferable.Alternatively, the bottom 21 of the notch could be formed in any manneras, for example, on a radius to be complimentary to the shape of theedge 16 of projection 15. The bottoms of the notches 20 are dimensionedso as to cause the arms and more precisely the edges 16 of projections15 to spread apart to a distance d,. This produces a spreading action onside strips or margins 11 and 12 which tends to increase the effectivelength L of each arm portion on either side of the projections 15 whileeach of the arm portions are restrained at their outer ends by the endpieces 13 and 14. This spreading action further introduces a torsionalstress in blade member 10. In the construction shown in FIG. 2 all ofthe arm portions are equal in length L and therefore the torsionalstress in all four arm portions is equal.

This stressing causes a dishing of blade 10 as more clearly exemplifiedin FIGS. 4 and 5. The post 19 may be initially inserted by bending thestrips or margins 11 and 12 so as to move the edges 16 of projections 15out of a coplanar relationship, then sliding the post member 19therebetween until the projections 15 are received in the notches 20.

This construction permits the blade to be self-retaining in the postunder all conditions and greatly enhances the assembly of the snap bladeassembly into a housing. This selfretaining preassembly substantiallyreduces overall assembly time of a complete switch as shown in FIG. 6.

An embodiment of the invention in a so-called doublemake, double-breakswitch is shown in FIG. 6. The switch 30, as diagrammaticallyillustrated in FIG. 6, comprises a generally cylindrical housing 30ahaving end walls 31 and 32. The end walls carry upper terminal members33 and 34 and lower terminal members 35 and 36 which are shown asgenerally L-shaped and having contacts 37, 38, 39 and 40 thereon adaptedto be contacted by contact pieces 41 and 42 carried by the blade 10.Defined in bottom wall 32 is a passage 43 adapted to act as a guide foran actuating plunger 43a. Extending downwardly from upper wall 31 is aspring guide 44 adapted to locate and retain a spring 45. Spring 45 isadapted to engage a seat 46 on a post 19. Actuator 19 at its upper endmay be formed in any suitable manner as shown by the seat 46 andextension 47 to receive spring 45. Spring 45 functions toact as areturn, as will hereinafter be described.

Each of the terminal members 33, 34, 35 and 36 has a leg 49 adapted toextend through a slot 50 in one of the end walls and be supportedtherein in operative spaced relation to the upper terminal. It will beunderstood that other structures for locking the terminal members to thehousing may be utilized. However, precise definitions of structure ofswitch housings are well known to those skilled in the art and are notrequired for a disclosure of the invention in this instance.

As shown in FIG. 6, the blade is in the position it would assume when itis in contact with terminals 37 and 38 under the bias of spring 45.

When the operator or a sensing device acting upon post 19 as, forexample, rod 43a moves upwardly against the bias of spring 45, contactpieces 41 and 42 engage contacts 37 and 38 as shown more clearly in FIG.7 and movement of post 19 will then cause the projections which act as afulcrum to snap over center to the position illustrated in FIG. 5. Theblade thus snaps from the position shown in FIG. 4 to that shown in FIG.5. At this time contacts 41 and 42 will be snapped over to terminals 39and 40, respectively. When the force on rod 43a is removed, the energystored in spring 45 will move post 19 downwardly as exemplified in FIG.8. The contacts 41 and 42 now engaging terminals 39 and 40 are limitedin movement. Upon further movement of post 19 under the bias of spring45,

the blade will snap back from the condition shown in FIG. 8 to thecondition shown in FIG. 4.

In this manner, the blade 10 snaps between its operating position whenthe end portions thereof are restrained from movement in one directionand the post 19 is moved in that direction a predetermined distance tosnap over center the projections 15.

The stressed blade as thus far disclosed has only two conditions ofstability, and must assume one of those two conditions due to thestresses in the arms and the interconnection thereof. The two ends ofthe blade must always be snapped in the same direction due to thestressing of the arms in both tension and torsion. There will be nococking of the blade upon movement thereof from one operating positionto another.

The blade 10 is, of course, of a conductive material and as illustratedin FIG. 6 is adapted to complete an electrical circuit between contacts37 and 38 or contacts 39 and 40. The positive bi-stability of the switchblade assures that there will be no cocking and resultantcrosscircuiting as by contacting terminals 33 and 36 or 35 and 34.

The invention thus far has been illustrated in conjunction with adouble-make, double-break switch adapted to make one of two circuits. Itis apparent that one of the set of terminals 33, 34 or 35, 36 could beeliminated an electrical conductors and some sort of stopping surface orabutment substituted therefor. For example, if the terminals 37 and 38were eliminated, or if no electrical connections were made thereto, theblade 10 under the influence of spring 45 would be in a normally closedposition when the circuit made thereby could be interrupted by theoccurrence of some condition which actuated rod 43a to open the circuit.For example, this type of application might be used in circuits withelectric lights which is designed to be illuminated when a door wasopened. For use in an application such as a starting circuit, theterminals 39 and 40 might be eliminated or not connected to an externalcircuit. Then, upon application of a force to rod 43a the blade 10 wouldcomplete a circuit between terminals 37 and 38 so long as the necessarypressure was exerted on post 19 through rod 43 a.

The invention may also be embodied in other snap acting applications,and where the post 19 is stationary and an actuating force is applied toone end of the blade.

In FIG. 9, a switch assembly comprising a blade 60 as shown in FIG. 1 ismounted to a post6l as shown in FIG. 2, which post is an extension of aterminal 62. Terminals 63 and 64 are carried in a housing 65 ofinsulating material having a cover portion 66. Terminals 63 and 64 havecontact portions 69 and 70, respectively, disposed in spaced apartrelation on either side of end 71 of blade 60. Mounted to blade 60 atend 71 is a contact 72. Disposed about a projection 73 on surface 74 isa spring 75, which through a spring end plate 76 acts on end 77 of blade60. Spring 75 acts to urge blade 60 to this position shown.

An actuating button or plunger 78 extends through cover 66 and whendepressed exerts a force on end 77 of blade 60 against the bias ofspring 75. When plunger 78 is depressed, end 77 is forced downwardlyagainst spring 75 while blade 60 is restrained at post 61. As thestresses in blade 60 are reversed, it snaps to its other stable stateand contact 72 will engage contact portion 70. When the force isreleased from plunger 78, spring 75 will snap blade 60 back to theposition shown.

In the assembly of FIG. 9 the distance of the ends 71, 77 of the bladeare asymmetrical with respect to post 61. Thus when an actuating forceis applied to the shorter end, as shown, a magnified or amplifiedmovement is obtained at the other end.

The spring 75, and also the spring 45 (FIG. 6) may be eliminated if theblades are given a permanent set in one degree of concavity. This may beaccomplished by initially inserting a spreading device as shown in FIG.2, and then heat treating the blade to impart the permanent set in onedegree of concavity. Such blades will always return to the permanent setcondition when an actuating force is removed. Accordingly, such a bladewould be considered to be monostable.

An embodiment of the invention wherein the blade is preformed is shownin FIGS. 10 and 11. A switch 79 comprises a housing member 80 having acover 81. Terminal members 82, 83 and 84 are mounted in housing member80. Terminal 82 has formed thereon a post 85 to which is mounted a blade86 in a manner hereinbefore described. One end of blade 86 which carriesa contact button 87 is adapted to make contact between either one ofterminals 83 or 84. The other end of blade 86 which may or may not carrya button 88 is captured between an abutment 89 on housing 80 and anabutment member 90 affixed to housing 80.

Blade 86 has been formed and mounted to post 85 and thereafter heattreated to impart a permanent set thereto as exemplified in FIG. 10.Alternatively, the blade might be heat treated on a first post and thentransferred to post 85. The degree of prestressing will depend on thedimension by which the blade is spread during the heat treatingoperation. An actuating member 91 has projections 92 arranged to engageblade 86 on the margins or strip portion thereof at projections 93.Downward motion of actuating member 91 through actuation of button 94will cause the blade to snap over to the position shown in broken linein FIG. 11. When the actuating force is released the preformed bladewill snap back to the position shown in full line in FIGS. 10 and 11.

FIG. 12 shows another embodiment of the invention in cross sectionwherein the blade may be allowed to remain in either one of its twostable states. Blade 96 is mounted to a post 97 which may be a terminalmember as shown in FIGS. 9 and 10. An actuating member 98 is formed todefine pockets 99 which receive the outer edges of the side strips ormargins of blade 96 adjacent the projections. Member 98 is provided witha recess 98a which slidably receives post 97. Connected to actuatingmember 98 is a button headed plunger 100 which permits the blade 96 tobe pushed to one stable position or pulled to the other. The overallhousing 101 and cover plate 102 may be otherwise formed as shown in FIG.10, and also may be utilized as a double-make, double-break arrangementto provide connection from a center terminal to outer terminals.

Reference is now made to FIGS. 1 and 2 and in particular FIG. 2. FIG. 2shows in broken line the areas of stress in the blade at its midpoint asit snaps from one position to the other. The areas indicated by Tgenerally represent tension, the areas indicated by C generally indicateareas of compression and the areas marked S generally indicate areas ofshear. It will be ap parent that with these stress distributions throughthe blade, the blade is in a very unstable condition and dependent onthe direction of motion of the post, will snap from one of its stablepositions to the other.

To minimize this stress concentration, the degree of curvature, or radiiR and R are made large to decrease the stress concentrations which wouldbe present about small radii or degrees of curvature. The radius R andindentation behind the projections serve an additional purpose inincreasing or extending the working length L in the arms 11a, 11b, 12a,12b without increasing the overall length of the blade. This furtherpermits the edges 16 of projections 15 to be elongated for additionalstability when mounted to post 19. The degree of permissible stressconcentrations at any point will depend on the application, size andmaterial of blade, etc., and the blade may be shaped accordinglydependent on these parameters.

To overcome any adverse effects which may be due to the stressconcentrations in the blade, a resilient post which will provide somestress relief as the blade snaps over may be utilized. An embodiment ofthe invention utilizing such a post is shown in FIGS. 13-15. The switchmechanism of FIGS. 13-15 may comprise a housing 104 of generallycylindrical shape having a bottom closure wall 105 which receivestherethrough an actuator and post carrying member 106. A post 106a, asmore clearly shown in FIG. 15, is formed of a resilient springy materialto provide notches 107 for the projections 108 of blade 109. Post 106ais carried in a recess 110 in actuator 106. The actuator and carrier106a has upstanding portions 110a which extend through blade 109 andreceive thereupon a spring seat 111. Spring seat 111 is formed with apassage 112 designed to receive an upstanding portion 113 of post 106a.The mechanism further includes terminal members 114 and 115 havingcontact portions 116 and 117, respectively, which are normally contactedby contact buttons 118 and 119, respectively, on the ends of blade 109.A spring 120 bears on seat 111 and at its upper end receives anotherseat 121. The blade 109 is normally in the position shown in FIG. 14 tocomplete a circuit between terminals 115 and 116. However, if the postcarrier and actuator 1060 is moved upwardly against the bias of spring120, the upward movement of post 106a will cause blade 109 to snapthrough and the terminal buttons 118 and 119 to engage the projections122 which may not have any electrical significance or may be electricalterminals (not shown). When the actuating force is removed from member106, spring seat 111 under the bias of spring 120 and bearing on theprojections 11011, 111 and/or shoulders 123 of post 106a will cause post106a to move downwardly and cause the blade 109 to again snap through tothe position shown in FIG. 14.

The post carrier and actuator 106 is designed to prevent any rotationalmovement of post 1060. The actuator 106 may have a tongue 124 thereonadapted to slidably be received in groove 125 in bottom wall member 105.

The resiliency of post 106a will permit it to be compressed at notches107 as the blade 109 moves through its unstable position as exemplifiedin FIG. 2. This decreases the stress concentrations in the blade andwill offer longer blade life. As the blade snaps through its centerpoint, the resilience of post 106 will expand post 106 at notches 107and aid in the snap action.

Another mechanism embodying the invention is shown in FIGS. 16 and 17.The mechanism of FIGS. 16 and 17 is the same as that of FIG. 14 exceptas otherwise shown. A housing 128 has a bottom wall 129 having anaperture 130 which receives an actuating member 131 therethrough. Member131 has a recess or well 131a defined therein conforming to thecross-sectional dimensions of a post 132 and receiving one end of thepost snugly therein. A snap blade 133 is mounted to post 132 aspreviously described. Carried on the upper end of post 132 is acap-shaped member 134 providing a spring seat on a flange 135 upon whicha return spring 136 is seated. Seat 134 defines a recess or well 137shaped to conform to the cross-sectional dimensions of post 132. Thisprovides a substantially rigid connection between post 132, actuatorI31, and member 134 to prevent relative rotation or cocking between themembers. Actuator 131 is maintained in predetermined position withrespect to housing 128 by one or more torques 138 on member 131 receivedin grooves 139 in bottom wall 129.

The blade 133 will snap to its other stable position when apredetermined force is exerted on actuator 131. When the force isreleased, spring 136 acting upon member 134 will urge post 132downwardly and blade 1133 will snap back to its original position.

In constructing the invention the blade is formed by one of thetechniques that have previously been described. Suitable materials areNo. 25 Beryllium copper and l77 Ph stainless steel, as well as springmaterials known as Havar and Elgilloy, having a relatively high Cobaltcontent. The formed blade is then heat treated. In the case of l7-7Condition C stainless steel, it may be heat treated for one hour atabout 900 F. Where it is desired to preform the blade for a monostableconstruction, it is heat treated while mounted to a post.

By way of example only, blades having an overall length of 0.650 inchesand a width of 0. l 85 inch have been constructed at a thickness of0.004 and 0.006 inches in stainless steel and Beryllium copper. Thedimension D, was 0.0l0 inches and dimension D varied to 0.035 inchgiving a spreading ratio of up to 3.5 to l. The length of the edges 16were 0.110 inch. This is substantially greater than the dimensions D andD which contributes to greater stability.

The foregoing dimensions are for illustrative purposes only to exemplifyrelative dimensioning of a blade constructed in accordance with theinvention. The dimensions of any particular blade and its post will bedetermined by the specifications of the environment in which it is towork and the functions it must accomplish.

The posts or spreaders are preferably formed of four-sided stock withthe notches defined in opposed sides. However, any post constructionwhich may be mounted to the blade in a stable arrangement may beutilized. For example, a double lead tapered screw may be inserted intoa cutout 17, FIG. 1, to obtain the desired degree of stressing of theblade.

While various embodiments of the invention showing appli' cations of theinvention have been disclosed, it is to be understood that the switchingconstruction embodying any of the features of the invention shown may becombined for a given application. The versatility of this switch bladeconstruction is exemplified by the fact that the blade may be used in asym metrical design merely as a circuit-breaking device with the postmovable or stationary or in a double-make, double-break device, againwith the post either movable by an actuating member or the poststationary and the actuating force applied to the blade.

Still further, the blade may be used in an asymmetrical design where onearm is longer than the other and additionally the post member may beconductive and form a portion of a terminal connector or be electricallyconnected to a terminal connector.

The invention is not limited to electrical applications. It may be usedin control systems operating on pneumatic, fluidic and hydraulicprinciples. Fluid forces may be applied to the blade or post to achievethe desired result in the same manner that mechanical forces areapplied.

It may thus be seen that the objects of the invention set forth as wellas those made apparent from the preceding description are efficientlyattained. Inasmuch as other embodiments of the invention may occur toothers skilled in the art, the appended claims are intended to cover allmodifications of the disclosed embodiments of the invention as well asother embodiments thereof which do not depart from the spirit and scopeof the invention.

What is claimed is:

l. A snap action blade assembly comprising a generally flat blade memberhaving spaced apart side strips joined at each end by end portions saidstrips being substantially longer than said end portions, said sidestrips having a dimension transverse to the length thereof substantiallygreater than the thickness of said blade, said strips having facingedges spaced apart a predetermined distance, a member having a dimensiongreater than said predetermined distance disposed between said stripsand engaging said edges and spreading said strips apart transverse tothe length thereof so as to tend to lengthen said strips and produce atorsional stress in said strips to produce concavity in one side of saidblade.

2. The blade assembly of claim 1 wherein said strips include inwardlydirected projections extending toward each other intermediate the endsof said strips, said projections defining said edges.

3. The blade assembly of claim 2 wherein said member is provided withnotches on opposite sides thereof, said notches receiving said edges ofsaid projections therein.

4. The assembly of claim 3 wherein said notches are defined in saidmember with a generally V-shape with the bottom of said notch beingsized and shaped to be essentially complimentary to the edge of theprojection received therein.

5. The assembly of claim 2 wherein said projections have essentiallyparallel spaced apart edges, the length of said edges contacting saidmember being substantially greater than said predetermined distancebetween the said edges.

6. The assembly of claim 3 wherein the walls defining said notches areangularly disposed at approximately thirty degrees.

7. The assembly of claim 2 wherein said projections have parallel spacedapart edges.

8. The assembly of claim 7 wherein said projections are relieved betweensaid edges thereof and the area where said projections join said strips.

9. The assembly of claim 3 wherein said spreading member is formed of aresilient material, so that said spreading member may elastically deformas said blade snaps between positions.

10. A snap blade construction comprising a housing means, a snap bladecarried by said housing means and having opposed end portions, saidblade having two substantially longitudinally disposed side stripsspaced from each other and integrally joined at each adjacent pair ofends thereof respectively to said end portions said side strips beingsubstantially longer than said end portions, said side strips eachhaving projections directed toward each other and defining facing edgesspaced apart a predetermined distance, and a post member having adimension greater than said predetermined distance disposed between saidprojections and bearing on the edges thereof to spread apart theprojections and torsionally stress said side strips and produceconcavity in one side of said blade, and means for applying an actuatingforce to one of said post member and said blade, whereby said blade willsnap between opposed positions of concavity relative to said housingmeans as said actuating force moves said blade or said post memberrelative to said housing means.

11. The construction of claim 10 wherein said post is stationary withrespect to said housing and said blade is snapped by afplication of aforce to one end thereof.

l The construction of claim 10 wherein said post is stationary withrespect to said housing and said blade is snapped by application of aforce to said projections.

13. The constructions of claim 10 wherein said post is movable along itslength, said housing member includes spaced apart abutments disposed oneither side of the ends of said blade, and said blade is snapped byapplication of a force to said post.

14. The construction of claim 13 further including a spring carried bysaid housing and acting on said post so that said spring has energystored therein when said switch is snapped by a force on said post andsaid spring will resnap said blade when the force on said post isreleased.

15. A snap blade construction as set forth in claim 10 wherein said sidestrips of said blade are substantially parallel to each other beforesaid blade is assembled to said actuator member.

16. A snap blade construction as set forth in claim 15 wherein saidprojections extend from the medial portion of said side strips, saidprojections define parallel spaced apart edges, and the dimensionallength of said edges are substantially greater than the dimensionbetween said edges.

17. A snap blade construction as set forth in claim 14 wherein saidprojections define arms between said projections and said end portionson each of said strips and said projections are relieved between saidedges and said strips to lengthen the effective length of said arms.

18. A snap blade construction as set forth in claim 10 wherein said sidestrips of said blade each has a bowed planar configuration with theelbow thereof being substantially medially disposed and facing the elbowof the other side strip before said blade is assembled to said actuatormember.

19. A snap blade construction as set forth in claim 10 wherein said posthas a substantially rectangular transverse cross-sectional configurationdefined by four flat sides thereof, grooves being provided in opposedflat sides of said actuator member for receiving the edges of saidprojections, said projections having straight free edges received insaid grooves.

20. The construction of claim 10 wherein said post is resilient betweenthe lines of contact of said projections thereon.

21. The construction of claim 10 wherein said blade is electricallyconductive and adapted to make and break electrical contacts. I

1. A snap action blade assembly comprising a generally flat blade memberhaving spaced apart side strips joined at each end by end portions, saidstrips being substantially longer than said end portions, said sidestrips having a dimension transverse to the length thereof substantiallygreater than the thickness of said blade, said strips having facingedges spaced apart a predetermined distance, a member having a dimensiongreater than said predetermined distance disposed between said stripsand engaging said edges and spreading said strips apart transverse tothe length thereof so as to tend to lengthen said strips and produce atorsional stress in said strips to produce concavity in one side of saidblade.
 2. The blade assembly of claim 1 wherein said strips includeinwardly directed projections extending toward each other intermediatethe ends of said strips, said projections defining said edges.
 3. Theblade assembly of claim 2 wherein said member is provided with notcheson opposite sides thereof, said notches receiving said edges of saidprojections therein.
 4. The assembly of claim 3 wherein said notches aredefined in said member with a generally V-shape with the bottom of saidnotch being sized and shaped to be essentially complimentary to the edgeof the projection received therein.
 5. The assembly of claim 2 whereinsaid projections have essentially parallel spaced apart edges, thelength of said edges contacting said member being substantially greaterthan said predetermined distance between the said edges.
 6. The assemblyof claim 3 wherein the walls defining said notches are angularlydisposed at approximately thirty degrees.
 7. The assembly of claim 2wherein said projections have parallel spaced apart edges.
 8. Theassembly of claim 7 wherein said projections are relieved between saidedges thereof and the area where said projections join said strips. 9.The assembly of claim 3 wherein said spreading member is formed of aresilient material, so that said spreading member may elastically deformas said blade snaps between positions.
 10. A snap blade constructioncomprising a housing means, a snap blade carried by said housing meansand having opposed end portions, said blade having two substantiallylongitudinally disposed side strips spaced from each other andintegrally joined at each adjacent pair of ends thereof respectively tosaid end portions said side strips being substantially longer than saidend portions, said side strips each having projections directed towardeach other and defining facing edges spaced apart a predetermineddistance, and a post member having a dimension greater than saidpredetermined distance disposed between said projections and bearing onthe edges thereof to spread apart the projections and torsionally stresssaid side strips and produce concavity in one side of said blade, andmeans for applying an actuating force to one of said post member andsaid blade, whereby said blade will snap between opposed positions ofconcavity relative to said housing means as said actuating force movessaid blade or said post member relative to said housing means.
 11. Theconstruction of claim 10 wherein said post is stationary with respect tosaid housing and said blade is snapped by application of a force to oneend thereof.
 12. The construction of claim 10 wherein said post isstationary with respect to said housing and said blade is snapped byapplication of a force to said projections.
 13. The constructions ofclaim 10 wherein said post is movable along its length, said housingmember includes spaced apart abutments disposed on either side of theends of said blade, and said blade is snapped by application of a forceto said post.
 14. The construction of claim 13 further including aspring carried by said housing and acting on said post so that saidspring has energy stored therein when said switch is snapped by a forceon said post and said spring will resnap said blade when the force onsaid post is released.
 15. A snap blade construction as set forth inclaim 10 wherein said side strips of said blade are substantiallyparallel to each other before said blade is assembled to said actuatormember.
 16. A snap blade construction as set forth in claim 15 whereinsaid projections extend from the medial portion of said side strips,said projections define parallel spaced apart edges, and the dimensionallength of said edges are substantially greater than the dimensionbetween said edges.
 17. A snap blade construction as set forth in claim14 wherein said projections define arms between said projections andsaid end portions on each of said strips and said projections arerelieved between said edges and said strips to lengthen the effectivelength of said arms.
 18. A snap blade construction as set forth in claim10 wherein said side strips of said blade each has a bowed planarconfiguration with the elbow thereof being substantially mediallydisposed and facing the elbow of the other side strip before said bladeis assembled to said actuator member.
 19. A snap blade construction asset forth in claim 10 wherein said post has a substantially rectangulartransverse cross-sectional configuration defined by four flat sidesthereof, grooves being provided in opposed flat sides of said actuatormember for receiving the edges of said projections, said projectionshaving straight free edges received in said grooves.
 20. Theconstruction of claim 10 wherein said post is resilient between thelines of contact of said projections thereon.
 21. The construction ofclaim 10 wherein said blade is electrically conductive and adapted tomake and break electrical contacts.